Volume 5, Number 6—December 1999
Emerging Infectious Diseases and Amphibian Population Declines
|Locality and date of mass deaths||Species affected and impacta||References|
|Chytridiomycosis||E. & S. Australia||Multiple montane rain forest and temperate||28-30|
|(1993-1999)b||species. Mass deaths, local extinctions,|
|population declines. Near-extinction|
|of Taudactylus acutirostris. Hypothesized|
|link with global extinction of two species|
|of gastric brooding frog (Rheobatrachus spp.).|
|W. Australia||Multiple species, predominantly the western||29,31|
|(1998-1999)c||green (or motorbike) frog (Litoria moorei).|
|Mass deaths, population declines.|
|Costa Rica||Multiple montane rain forest species.||20,23,|
|and Panama||Mass deaths, local extinctions, population||28,29|
|(1994-99)||declines. Hypothesized link with global|
|extinction of golden toad, Bufo periglenes.|
|Ecuador (1999)||Montane rain forest Atelopus species, Telmatobius||29|
|niger, and Gastrothecus pseustes. Unknown impact.|
|Arizona||Leopard frog (Rana yavapiensis &||29|
|(1996-1997)||R. chiricahuensis). Mass deaths.|
|S. Arizona (1999)||Leopard frog (Rana sp.). Mass deaths.||31,32|
|Colorado (1999)||Boreal toad (Bufo boreas). Mass deaths.||d|
|Colorado (1970s)||Leopard frog (Rana pipiens). Mass deaths.||32d|
|Sierra Nevada,||Yosemite toad (Bufo canorus). Mass deaths.||32e|
|Ranaviral disease||United Kingdom||Common frog (Rana temporaria). Mass deaths,||5,16,26,|
|(1992-1999f)||possibly population declines.||33,34|
|Arizona (1995)||Sonoran tiger salamander (Ambystoma tigrinum||27|
|stebbinsi). Mass deaths in this endangered species.|
|N. Dakota (1998)||Tiger salamander (A. tigrinum).||35|
|Maine (1998)||Tiger salamander (A. maculatum).||35|
|Utah (1998)||Tiger salamander (A. tigrinum). Mass deaths.||35|
|Saskatchewan,||Tiger salamander (A. tigrinum diaboli). Mass deaths.||36|
aMass deaths did not occur in all cases of wild amphibians infected by chytridiomycosis. Bufo americanus from Maryland and Acris crepitans from Illinois have been found infected with chytridiomycosis without observed deaths (37,38). In Australia, chytridiomycosis has been reported from small numbers of amphibians without evidence of clinical signs or deaths in both upland and lowland species (R. Speare, L. Berger, unpubl. obs.).
bRetrospective studies have identified chytridiomycosis as the cause of death in wild frogs in five Australian states from as early as 1989 (29).
cThis recent outbreak was more than 2,000 km from the closest recorded chytridiomycosis-linked amphibian die-offs (31). It is thought that chytridiomycosis may now be enzootic in many areas of Australia, but still in the process of spreading to naïve populations. A role for chytridiomycosis in other recent W. Australian declines is suspected due to similarities in the pattern of declines and presence of the Batrachochytrium carcasses from W. Australia since 1992.
dD.E. Green, unpubl. obs.
eD.E. Green, unpubl. obs. Historically collected specimens recently examined histologically revealed chytridiomycosis as a contributing factor to the cause of death in 2 of 12 animals.